The present invention relates generally to control valves and, more specifically, to a control valve that includes an annular poppet check valve.
In automotive engines, an increasing number of control functions are being actuated using engine oil pump pressure. For cylinder deactivation systems, it is necessary to ensure that moving components, such as cylinder valve lifters, are exposed to positive oil pressure for lubrication. Pressure between the cylinder valve lifters and the oil control valve used to deactivate the lifters also helps to reduce hydraulic compliance that could limit the pressure response of the engine cylinder deactivation system.
Referring now to FIG. 1, in some control valves used in engine cylinder deactivation systems, such as cylinder deactivation system 100, an oil pump 103 can supply pressurized fluid to a control valve 102 that can be connected to a cylinder valve lifter 101. The oil pressure between the cylinder valve lifter 101 and the oil control valve 102 can be maintained by using low pressure check valves 104 built into the oil control valve 102. These low pressure check valves 104 can include balls 106 held against ball seats 112 by springs 108. The balls 106 can block the flow of the oil from the lifter passages 110 to an oil tank 111 until the oil pressure in the lifter passages 110 creates a force on the ball seats 112 greater than or equal to the force of the spring load. Once the oil pressure in the lifter passage 110 creates enough force, the check valve ball 106 can lift off of the ball seat 112, and the oil can flow past the balls 106 as long as the pressure force exceeds the spring force. The oil flow into the lifter passage 110 can either be supplied by orifice 114 in the oil control valve 102 or an orifice 116 positioned remotely from the control valve 102 between the cylinder valve lifter 101 and the pump 103.
There are some disadvantages to the ball style pressure check valves for application in an engine. In this typical arrangement, the passages, including the check valve seat area, are oriented radially outward from the valve bore 105. Sufficient space for the flow passage, seat area, ball, and spring is required. Having this space requirement means that the diameter of the valve body, and thus the cavity in the engine, have to be large enough to accommodate these parts. Also, the flow passage into the check valve and the ball seat area are necessarily the same size, so the only way to increase the flow area in this design is to also increase the ball size or use multiple check valves in parallel. Bigger balls and multiple check valves increase the size of the overall valve package and the number of components. Further, the check valve springs often are difficult to produce and assemble due to the low force and spring rate design criteria required to maintain the typical low hydraulic pressure.
Thus, it would be advantageous to have a control valve including a check valve that allows for more control over the flow rate of a fluid without having to adjust the size of the check valve.